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https://issues.apache.org/jira/browse/LANG-1341?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Kevin Binswanger updated LANG-1341:
-----------------------------------
Summary: equalsBuilder.appendSuper() has incorrect behavior if the object
you call equals() on is a direct supertype of Object (was:
equalsBuilder.appendSuper() always fails if one of the two classes is a direct
subtype of Object)
> equalsBuilder.appendSuper() has incorrect behavior if the object you call
> equals() on is a direct supertype of Object
> ---------------------------------------------------------------------------------------------------------------------
>
> Key: LANG-1341
> URL: https://issues.apache.org/jira/browse/LANG-1341
> Project: Commons Lang
> Issue Type: Bug
> Reporter: Kevin Binswanger
> Priority: Minor
>
> If you use EqualsBuilder.appendSuper(super.equals(Object)) on an Object whose
> direct supertype is Object, it will succeed if and only if the two references
> are the same (because that's what Object.equals does).
> Reading it out loud, this is obvious, but I think the Javadoc for
> EqualsBuilder encourages you to make this mistake. In particular, here's some
> text in the summary of the Javadoc:
> {quote}Typical use for the code is as follows:{quote}
> {code}
> public boolean equals(Object obj) {
> if (obj == null) { return false; }
> if (obj == this) { return true; }
> if (obj.getClass() != getClass()) {
> return false;
> }
> MyClass rhs = (MyClass) obj;
> return new EqualsBuilder()
> .appendSuper(super.equals(obj))
> .append(field1, rhs.field1)
> .append(field2, rhs.field2)
> .append(field3, rhs.field3)
> .isEquals();
> }{code}
> There's also no mention of this in the javadocs for the appendSuper() method
> itself.
> My suggestion is to fix the example at the beginning. The way HashCodeBuilder
> does this, which I think is the best, is to leave appendSuper out of the
> example and adds this line after: {quote}If required, the superclass
> hashCode() can be added using appendSuper(int).{quote}
> For completeness, here's a snippet of code that illustrates this problem.
> {code}
> public class Thing {
> public String text;
> @Override
> public boolean equals(final Object other) {
> if (other == null) {
> return false;
> }
> if (other == this) {
> return true;
> }
> if (other.getClass() != getClass()) {
> return false;
> }
> final Thing thing = (Thing) other;
> return new EqualsBuilder()
> .appendSuper(super.equals(other))
> .append(text, thing.text)
> .isEquals();
> }
> }{code}
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